fix(time): pluralize nil-service relative time fallback

Co-Authored-By: Virgil <virgil@lethean.io>

time.go

@@ -43,7 +43,7 @@ func FormatAgo(count int, unit string) string {
 	svc := Default()
 	unit = normalizeAgoUnit(unit)
 	if svc == nil {
-		return core.Sprintf("%d %ss ago", count, unit)
+		return core.Sprintf("%d %s ago", count, Pluralize(unit, count))
 	}
 	key := "time.ago." + unit
 	result := svc.T(key, map[string]any{"Count": count})

time_test.go

@@ -192,6 +192,20 @@ func TestFormatAgo_Good_SingularUnit(t *testing.T) {
 	assert.Equal(t, "1 fortnight ago", got)
 }
 
+func TestFormatAgo_Good_NoDefaultService(t *testing.T) {
+	prev := Default()
+	SetDefault(nil)
+	t.Cleanup(func() {
+		SetDefault(prev)
+	})
+
+	got := FormatAgo(1, "second")
+	assert.Equal(t, "1 second ago", got)
+
+	got = FormatAgo(5, "second")
+	assert.Equal(t, "5 seconds ago", got)
+}
+
 func TestFormatAgo_Good_FrenchRelativeTime(t *testing.T) {
 	prev := Default()
 	svc, err := New()